JP2002075033A - Back light device and display device provided with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of components and assembling man-hours of a back light device and a display device. SOLUTION: The back light device, wherein an optical sheet 4 is disposed all over the light guide plate 2 for guiding the light of a light source, is characterized by using a terminal strip 14 included with the back light device so as to prevent the detachment of the optical sheet 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a backlight device suitable for a flat display device represented by a liquid crystal display device and a display device provided with the same.

[0002]

2. Description of the Related Art In a backlight device used for a flat display device represented by a liquid crystal display device, a light source is disposed on a side surface of a light guide plate, and a light diffusion sheet, a prism lens sheet, or the like is provided on one surface of the light guide plate. One or a plurality of optical sheets are arranged. In the process of assembling the optical sheet into the display device, the optical sheet is fixed to a frame located on the back side of the metal front frame of the display device using a single-sided or double-sided adhesive tape or the like.

[0003]

The structure for fixing an optical sheet with an adhesive tape as described above requires an extra part called an adhesive tape. Further, in the assembling work, there are problems such as a workability in positioning the optical sheet and a defect due to a sticky foreign matter generated from the adhesive tape. Further, since the edge of the optical sheet is fixed with the adhesive tape, thermal expansion and contraction of the optical sheet are hindered, which causes a factor of generating distortion and wrinkles in the optical sheet.

In view of the above, an object of the present invention is to reduce the number of components and the number of assembling steps of a backlight device and a display device. Another object is to prevent distortion and wrinkles from occurring on the optical sheet.

[0005]

According to a first aspect of the present invention, there is provided a backlight device in which an optical sheet is disposed on one surface of a light guide plate for guiding light from a light source. A terminal plate attached to the optical sheet is used for preventing the optical sheet from coming off.

According to a second aspect of the present invention, there is provided a backlight device having an optical sheet disposed on one surface of a light guide plate for guiding light from a light source, and a display device disposed on the backlight device. Display panel, and a display device having a metal front frame covering the outer peripheral portion of the display panel, wherein the optical sheet is detached by using a terminal plate attached to the backlight device so as to be in contact with the front frame. It is characterized by stopping.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described.
This will be described with reference to the drawings. 1 is a plan view of the backlight device 1, FIGS. 2 to 4 are enlarged views of a portion surrounded by circles A to C in FIG. 1, and FIG. 5 is a cross-sectional view along AA-AA of FIG. 2. 6 is a cross-sectional view of the liquid crystal display device corresponding to FIG.

In the backlight device 1, a light source unit 3 is disposed so as to face a side surface of a light guide plate 2, and an optical sheet 4 is disposed on one surface serving as a light emitting surface, in this example, an upper surface. The light guide plate 2 is formed by processing a resin plate, such as acrylic, having good light transmittance into a rectangular shape. The light source unit 3 arranges a linear light source formed of a cold cathode tube or the like along a predetermined side, in this example, a long side so as to face the side surface of the light guide plate 2,
A light reflecting member is arranged around the periphery.

A resin frame 5 is arranged around the light guide plate 2 so as to support the edge of the light guide plate 2. This frame 5
The light guide plate 2 is about the same thickness as the light guide plate 2, and the light guide plate 2 is removably accommodated in a concave portion inside the light guide plate 2. Frame 5
Can be formed integrally with the light guide plate 2, for example, 2
Both can be integrally formed by color molding or the like.

The optical sheet 4 is formed by laminating a plurality of light diffusing sheets and prism lens sheets having the same planar shape, but may be constituted by only one sheet. As shown in FIGS. 2 and 3, a pair of tongue-shaped pieces 6 and 7 used to prevent the optical sheet from coming off are formed on a predetermined side of the optical sheet, in this example, a short side. The tongues 6 and 7 have holes 6 for positioning.
a, 7a are formed.

In correspondence with the positioning holes 6a, 7a, bosses 8, 9 penetrating the holes 6a, 7a are integrally formed on the upper surface of the backlight device 1, as shown in FIGS. Is formed. In this example, the tongues 6 and 7 are arranged outside the light guide plate 2 and the bosses 8 and 9 are formed on the upper surface of the frame 5 located thereunder. Light guide plate 2
Bosses 8 and 9 can be formed integrally with the light guide plate 2.

A predetermined side of the optical sheet 4, in this example, a long side opposite to the side where the linear light source is disposed,
As shown in FIG. 3, a pair of positioning tongue-shaped pieces 10, 11 are formed. Small reference surfaces 12 and 13 are formed on the upper surface of the backlight device 1 so that one side of the tongue-shaped pieces 10 and 11 can be in contact with each other for positioning. The reference surfaces 12 and 13 are formed on the frame 5 located outside the light guide plate 2.

At the four corners of the backlight device, there are provided terminal plates 1 attached to the device for electrical connection or reinforcement.
4, 15, 16, and 17 are arranged. Terminal board 14-1
Numeral 7 is formed by bending a conductive metal plate into a U-shape, and in this example, it is attached so as to sandwich the upper and lower portions of the resin constituting the short side of the frame 5. The terminal plates 14 to 17 are fixed to the terminal plates 14 to 17 by bending portions 14 a to 17 a into small holes of the frame 5. In the terminal plates 14 to 17, in addition to semicircular through holes 14b to 17b without a circle for fixing to an external device, through holes 14c to 17c for screwing used for ground connection or the like are formed. ing.

Of the terminal plates 14 to 17, the terminal plates 14, 15 arranged adjacent to the bosses 8, 9 are held by the bosses 8, 9 by partially pressing the optical sheet 4. A holding portion 14d is provided on one side of the optical sheet 4 so that a metal fitting for preventing the optical sheet 4 from coming off can also be used.
15d are integrally formed. These holding parts 14d, 15d
Is overlapped with the tongue pieces 6 and 7 of the optical sheet 4,
The bosses 8 and 9 are formed to have a length reaching the vicinity thereof.
Semi-circular cutouts into which the bosses 8 and 9 fit are formed at the tips of the holding portions 14d and 15d.

The backlight device 1 is assembled as follows. First, a linear light source is arranged together with a reflecting member so as to face one side surface of the light guide plate 2 to form an assembly unit to which the light source unit 3 is attached. This assembly unit is inserted into the frame 5. Depending on the structure of the light source unit 3 and the frame 5, the light source unit 3 may be arranged on the side surface of the light guide plate 2 after the light guide plate 2 is inserted into the frame 5. It is effective to apply a surface treatment to the lower surface of the light guide plate 2 to enhance the reflectivity or to arrange the reflective sheet 2a in order to increase the light use efficiency.

Next, the optical sheet 4 is laminated on the light guide plate 2. Here, one side (short side direction) of the sheet 4 is positioned by abutting one side of the tongue-shaped pieces 10, 11 spaced apart from each other on the reference surfaces 12, 13 of the frame. Further, the bosses 8 and 9 are passed through the holes 6a and 7a of the tongue-shaped pieces 6 and 7 spaced from each other, thereby positioning the sheet 4 in another direction (longitudinal direction) and positioning the sheet 4 in the plane direction. Movement prevention is performed.

Next, the terminal plates 14 to 14 are mounted on the frame 5 from the side thereof.
Slide 17 on. With this mounting, the holding portions 14d and 15d are positioned on the tongue-shaped pieces 6 and 7 so as to hold the tongue-shaped pieces 6 and 7, and the tongue-shaped pieces 6 and 7 are prevented from coming off the bosses 8 and 9 as a part of the terminal plate. The blocking of the optical sheet 4 is prevented by the blocking by the 14d and 15d.

The terminal plates 14 and 15 are connected to the other terminal plates 1.
Along with 6 and 17, the optical sheet 4 can be mounted on the frame 5 before mounting. In this case, the optical sheet 4
The holding portions 14d, 15d are bent upward in advance to near the height positions of the bosses 8, 9 so that the holding portions 14d, 15d do not hinder the mounting of the holding members 14d, 9d on the bosses 8, 9; , 15d are bent downward and the sheet 4
May be stopped.

After the backlight device 1 is assembled in this manner, the liquid crystal display device 18 is assembled as shown in FIG. That is, the display panel, in this example, the liquid crystal display panel 19 is arranged so as to be stacked on the backlight device 1, and the metal front frame 20 is attached so as to cover the periphery thereof. The front frame 20 is fixed by locking a part thereof to the frame 5 or the like of the backlight device 1. By this fixing, the front frame 20 is electrically connected to the terminal plates 14 to 17 of the backlight device 1,
In order to perform this more reliably, a part of the front frame 20 is screwed and fixed to the hole portions 14c to 17c of the terminal plates 14 to 17. By this screwing, the metal part disposed in the light source part 3, for example, a metal reflecting member and the terminal part 14 are electrically connected on the back side of the terminal part 14. Further, the terminal plate 14 and the terminal plate 1
The ground pattern (not shown) on the circuit board disposed between the terminals 5 and 5 is electrically connected to the terminal plate 14 or the terminal plate 15. As a result, a display in which the metal parts forming the front frame 20 and the light source unit 3 are electrically connected to the ground (ground) potential via the terminal plate 14 or the terminal plate 15 to prevent generation of unnecessary radiation (EMI countermeasure). An apparatus can be provided.

As described above, since the optical sheet 4 can be prevented from coming off using the components required for the backlight device 1, the number of components and the number of assembling steps can be reduced. Further, since the optical sheet 4 is mounted with play on the bosses 8 and 9, it is possible to secure a higher degree of freedom of deformation of the optical sheet 4 as compared with a case where the optical sheet 4 is fixed with an adhesive tape or the like. It is possible to provide a structure in which distortion and wrinkles due to expansion and contraction such as a heat cycle are less generated. Further, as compared with the case where the optical sheet 4 is fixed to the frame 5 with an adhesive tape or the like, the occurrence of scratches on the optical sheet 4 due to friction between the optical sheet 4 and the light guide plate 2 can be suppressed. .

In the above embodiment, the terminal plate 14
17 to 17, the optical sheet was prevented from coming off by using two terminal plates 14 and 15 arranged on one short side of the backlight device 1, but other terminal plates were also used to prevent the optical sheet from coming off. You may use it. For example, the terminal plates 14 and 16 located above the backlight device 1 may be used to prevent the optical sheet from coming off. In particular, when incorporated into a final product such as a personal computer or the like, if the end of the sheet 4 located above is fixed by the terminal plates 14 and 16, the movement of the sheet 4 can be minimized. In addition, all of the terminal plates 14 to 17 arranged at the four corners may be used to prevent the optical sheet from coming off. Further, the backlight device 1, particularly, its light source unit 3
The terminal plates 14 to 17 can be arranged on the long side of the backlight device 1 depending on the shape and arrangement of the backlight device 1. Therefore, the optical sheet 4 may be prevented from coming off using the terminal plate arranged on the long side. .

In the above embodiment, a liquid crystal display device is taken as an example. However, the present invention can be applied to a display device in which a display panel other than a liquid crystal panel is arranged on a backlight device.

[0023]

As described above, according to the present invention, it is possible to provide a backlight device in which the number of parts and the number of assembling steps are reduced, and a display device using the same. Further, the quality of the optical sheet can be kept good, and the state of the backlight device can be maintained in a stable state.

[Brief description of the drawings]

FIG. 1 is a plan view illustrating an embodiment of a backlight device according to the present invention.

FIG. 2 is an enlarged view of a portion A in FIG.

FIG. 3 is an enlarged view of a portion B in FIG. 1;

FIG. 4 is an enlarged view of a portion C in FIG. 1;

FIG. 5 is a sectional view taken along the line AA-AA in FIG. 2;

6 is a cross-sectional view of the liquid crystal display device, which is a cross-sectional view of a portion corresponding to FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Back light device 3 Light source part 4 Optical sheet 5 Frame 14 Terminal board 15 Terminal board

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazutoshi Katsukawa 3-201 Minamiyoshikata, Tottori City, Tottori Prefecture Inside Sanyo Electric Co., Ltd. (72) Inventor Takashi Taniguchi 3-201 Minamiyoshikata, Tottori City, Tottori Prefecture Sanyo Tottori Inside Electric Co., Ltd. (72) Inventor Akio Tanishige 3-201, Minamiyoshikata, Tottori-shi, Tottori Prefecture Sanyo Electric Co., Ltd. (72) Inventor Seiji Morimoto 3-201, Minamiyoshikata, Tottori-shi, Tottori Prefecture Sanyo Electric Co., Ltd. F-term (reference) 2H089 HA40 QA13 TA16 TA18 TA20 2H091 FA14Z FA16Z FA21Z FA23Z FA41Z LA30 5G435 AA17 BB12 BB15 EE01 EE11 FF06 KK03 KK05

Claims (2)

[Claims] 1. A backlight device in which an optical sheet is disposed on one surface of a light guide plate for guiding light from a light source, wherein a terminal plate attached to the backlight device is used for preventing the optical sheet from coming off. Backlight device. 2. A backlight device in which an optical sheet is disposed on one surface of a light guide plate for guiding light from a light source, a display panel disposed on the backlight device, and a metal cover for covering an outer peripheral portion of the display panel. In a display device having a front frame,
A display device, wherein the optical sheet is prevented from coming off using a terminal plate attached to the backlight device so as to be in contact with the front frame.